]\IoRRis: Chestnut Bught Resistance 



37 



GIANT CHESTNUT IN EASTERN CHINA. 



Although the bark disease is found in the groves of this region, the Chinese species (C. mollis- 

 sima) seems to have acquired a high degree of immunity to it. This photograph, taken 

 at San tun ying, province of ChiH, shows scars on the tree, where the disease has made 

 its appearance but been overcome. A large number of seeds of trees of this species have 

 recently been introduced by the deoartment of agriculture and distributed among 

 investigators in the United States. (Figure 14.) 



different degrees of resistance to the 

 blight. Some of them which show an 

 occasional blighted limb may be pre- 

 served with a moderate degree of care. 

 This is also true of the seedlings of 

 European and Asiatic varieties. None 

 of them appear to be as vulnerable as the 

 American chestnut, but most of mine 

 are dead nevertheless. 



Korean chestnuts and chestnuts from 

 the Aomori region in Japan resisted the 

 blight almost completely until they were 

 six years of age. Since that time they 

 have shown a marked tendency to 

 blight, but resist it better than docs the 

 American chestnut. 



Korean and Japanese chestnuts when 

 grafted upon American chestnut sprouts 

 all blighted in their second or third 

 year after grafting while their' ' parents ' ' 

 remained unblighted, indicating that 



the sap of the American chestnut fur- 

 nishes attractive pabulum for Endothia. 

 American chestnuts grafted upon stocks 

 of Korean and northern Japanese chest- 

 nuts showed a marked tendency to 

 blight promptly, near the point of 

 union of the graft, while the stocks 

 remained unblighted. 



One hybrid between the American 

 sweet chestnut and the chinquapin 

 blighted when about eight years of age 

 and is now dead. 



None of the American species of 

 chinquapin, varying from five years to 

 about thirteen years of age, has blighted, 

 with the exception of two limbs, which 

 were injured by falling limbs of a 

 blighted American sweet chestnut tree. 

 These injured and blighted branches 

 were removed and there has been no 

 other blight among the chinquapins. 



